A hapten, dinitrophenol (DNP) was coupled to proteins and to carbohydrates and used to immunize guinea pigs, skin test them, induce immunologic tolerance in them and to determine the inhibitory effect of such hapten on the migraton of the peritoneal exudate cells. DNP-sucrose polymers induced immediate and delayed sensitivity and in sufficient quantity tolerance, in animals immunized with that material or with DNP-protein conjugates. DNP-sucrose polymers inhibited the migration of peritoneal exudate cells of animals immunized with DNP-protein conjugates, but did not alter the migration of leukocytes of animals immunized with protein without DNP. These effects may be mediated by bone marrow lymphocytes since DNP-sucrose did not effect a thymus cell mediator reaction, i.e., skin reaction, to dinitrochlorobenzene in animals immunized with that material. The work shows delayed sensitivity can be directed to a hapten, i.e., be specific for the hapten and independent of the carrier.